When transporting cargo by truck, railcar, plane or ship, it is usually necessary to secure the cargo in place. Undesired movement of the cargo during transport can cause any of a number of undesired consequences, ranging from damage of the cargo to dangerous instability of the transporter (e.g., tipping of a truck trailer).
Suitable devices for securing cargo should not only provide rigid and stable support, but should also be easily inserted in and removed from their appropriate location. In addition, cargo securing devices should be constructed so as not to damage either the cargo or the freight container itself.
One particularly critical use of cargo securing devices is in the transportation of postal containers. The postal containers currently used by the United States Postal Service weigh approximately 2,100 pounds when fully loaded, and have rollers on the bottom to provide mobility. One drawback, however, is that the postal containers tend to move while being transported, and thus a rigid securing device is needed. The devices currently used to secure these postal containers suffer from numerous drawbacks, and have damaged the interior walls of truck trailers and also failed resulting in postal containers being ejected from the rear of truck trailers. Obviously, the loss of a postal container through the back of a truck trailer is not only unacceptable in terms of delivery of mail, but also creates an extreme danger to other vehicles traveling behind the truck.
One device that is commonly used for securing postal containers is that shown by U.S. Pat. No. 4,079,677, issued to Vandergriff, et al. A nearly identical device is also shown on page 20 of the Kinedyne Corp. Cargo Control System catalog (1991). The devices shown in the Vandergriff patent and the Kinedyne catalog typically are made from extruded aluminum, and can be extremely heavy. Another significant drawback of these devices is that since aluminum has a high salvage value, these devices are prone to be stolen.
The devices shown by Vandergriff and the Kinedyne catalog are designed to be attached to mounting tracks, often referred to as E-Track rails, which are secured to opposite sides of the freight container. Each E-Track rail generally comprises a series of rectangular openings through which a latching member may be inserted. Another major drawback of the Vandergriff and Kinedyne devices is that they are generally designed to be used with some type of weight on top of the devices. Thus, one often places decking on top of these devices, and then places more cargo on top of the decking. Due to the dimensions and weight of postal containers, such stacking is not possible. Without weight on top of the devices, the securing bars of Vandergriff and Kinedyne tend to come out of the E-Track rail while being transported, thereby creating the hazards referred to above.
Another device currently being used to secure postal containers in truck trailers are nylon shoring straps, as shown on page 15 of the Kinedyne catalog. While the latching means utilized on these straps generally can be more rigidly held in place by the E-Track rail, these straps suffer from several drawbacks. These straps are subject to tearing or otherwise separating, and if tensioned too tightly may pull the E-Track rail away from the side walls of the trailer. Furthermore, these straps may loosen during transit, thereby permitting the postal containers to move about.
Consequently, the present inventors were faced with the problem of devising a more reliable, inexpensive, and easily-handled cargo shoring assembly.